The M5 has a specific issue with the headers. The headers go all the way under the car to the middle of the transmission so it's impossible to use a transmission jack on the 280. I had to modify my transmission jack and still couldn't strap the transmission to it tightly. In addition to this, I'm sure everyone knows about the crazy Torx bolts. I have 2 lifts and a full telescoping, tilting, swiveling transmission jack, but even with those tools, it was such a pain that I decided right there the Getrag 280 is not going back in.
Here is a picture of the JB Racing flywheel and new clutch.
The bell housing has to come from a 1985 535i. These are available new from BMW for about $250 if you can't find a used one. I use an input shaft to align the clutch because the plastic tool has too much play in it. The separate bell housing makes it more difficult to reposition the clutch if the transmission doesn't go it. So, I made sure the alignment was perfect using the input shaft -- it fits much better than the plastic tool. You have to install the slave cylinder to hold the throwout bearing in-place. After the transmission is in there, you have to remove the slave cylinder to tighten the upper nut. One last check on the alignment:
The sensors fit but they are "clocked" differently than on the Getrag 280. Because of this, the heat shield installs with different holes. The heat shield has three holes in it and you have to use a different set of holes to install on the Getrag 265.
There is a lot of conflicting information out there about the compatibility of a Getrag 265 and a Getrag 280. I measured both and the 265 is about 6mm longer at the output flange and about 10mm longer at the selector shaft. The standard E28 M5 driveshaft will work with the 265. The center bearing has room to move because the mounting bolts are in slots.
The aluminum shift arm will not fit on a stock 265 because that transmission is designed to work with the sheet metal shift arm. One option is to install all the shifting parts from a 1985 535i. I like the aluminum shift arm so I decided to adapt the transmission to work with it. The E30 M3 has adapter parts (25 11 2 225 369, about $10) for installing the aluminum shift arm to a Getrag 265. The problem with this part on an E28 M5 is that it uses a special length shift arm. I wanted to keep all the E28 M5 shifting parts, so I moved the mount point to the correct location. If you cut 27mm off the "ears" on a Getrag 265, it puts the shift arm in the correct location relative to the selector shaft:
The easy way to do this is by drilling the holes deeper before cutting off the ears, that way, you just need to tap it for M8x1.25 and everything lines up.
With the "bow" installed, the aluminum shift arm will fit in there and the pin (25 11 2 225 344, about $10) with an M8 nut will hold it in place. It's best to install the bow with pin and nut on the end of the shift arm and then bolt the bow to the ears after the transmission is installed.
Here is a shot of the shifter. One other minor change is the location of the reverse switch. The switch is on the other side of the transmission so you have to re-route the reverse light wires.
I tried several different transmission mounts including the M3 mount, and it looks like you have to use the 1985 535i crossmember and specific (angled) rubber mounts that go with it.
I'll have driving impressions later.
